Present methods for connecting parallel machines (e.g., IBM's 9076, models SP1 and SP2) to external LANs and WANs use a general purpose computer as an Internet Protocol (IP) Router. This method, however, is a low bandwidth, long latency, and expensive solution.
An alternative method is to use a general purpose LAN hub as the router, instead of a general purpose computer. However, there are many different types of hubs, each with a different method for transferring data among the many LAN and WAN adapter boards. It is very costly to build special parallel machine adapters for each one of these hubs.
A third method is to use a gateway router computer. A gateway router computer, however, cannot guarantee deterministic (or low variance) latency, as required for applications such as video servers. We define latency as the time it takes for a packet of data to traverse through a device, a gateway in this instance. Future applications that require high performance asynchronous transfer mode ("ATM") networks (for sending, e.g., video information) require guaranteed delivery of data packets at a deterministic interval. Therefore, the latency must be known beforehand. Otherwise, large amounts of buffering are required at the receiving end to smooth out the uneven delivery of data packets.